1 //===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the Link Time Optimization library. This library is
11 // intended to be used by linker to optimize code at link time.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/LTO/legacy/LTOCodeGenerator.h"
16 
17 #include "llvm/ADT/Statistic.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/Analysis/Passes.h"
20 #include "llvm/Analysis/TargetLibraryInfo.h"
21 #include "llvm/Analysis/TargetTransformInfo.h"
22 #include "llvm/Bitcode/ReaderWriter.h"
23 #include "llvm/CodeGen/ParallelCG.h"
24 #include "llvm/CodeGen/RuntimeLibcalls.h"
25 #include "llvm/Config/config.h"
26 #include "llvm/IR/Constants.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/DebugInfo.h"
29 #include "llvm/IR/DerivedTypes.h"
30 #include "llvm/IR/DiagnosticInfo.h"
31 #include "llvm/IR/DiagnosticPrinter.h"
32 #include "llvm/IR/LLVMContext.h"
33 #include "llvm/IR/LegacyPassManager.h"
34 #include "llvm/IR/Mangler.h"
35 #include "llvm/IR/Module.h"
36 #include "llvm/IR/Verifier.h"
37 #include "llvm/InitializePasses.h"
38 #include "llvm/LTO/legacy/LTOModule.h"
39 #include "llvm/LTO/legacy/UpdateCompilerUsed.h"
40 #include "llvm/Linker/Linker.h"
41 #include "llvm/MC/MCAsmInfo.h"
42 #include "llvm/MC/MCContext.h"
43 #include "llvm/MC/SubtargetFeature.h"
44 #include "llvm/Support/CommandLine.h"
45 #include "llvm/Support/FileSystem.h"
46 #include "llvm/Support/Host.h"
47 #include "llvm/Support/MemoryBuffer.h"
48 #include "llvm/Support/Signals.h"
49 #include "llvm/Support/TargetRegistry.h"
50 #include "llvm/Support/TargetSelect.h"
51 #include "llvm/Support/ToolOutputFile.h"
52 #include "llvm/Support/raw_ostream.h"
53 #include "llvm/Target/TargetLowering.h"
54 #include "llvm/Target/TargetOptions.h"
55 #include "llvm/Target/TargetRegisterInfo.h"
56 #include "llvm/Target/TargetSubtargetInfo.h"
57 #include "llvm/Transforms/IPO.h"
58 #include "llvm/Transforms/IPO/Internalize.h"
59 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
60 #include "llvm/Transforms/ObjCARC.h"
61 #include <system_error>
62 using namespace llvm;
63 
getVersionString()64 const char* LTOCodeGenerator::getVersionString() {
65 #ifdef LLVM_VERSION_INFO
66   return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
67 #else
68   return PACKAGE_NAME " version " PACKAGE_VERSION;
69 #endif
70 }
71 
72 namespace llvm {
73 cl::opt<bool> LTODiscardValueNames(
74     "lto-discard-value-names",
75     cl::desc("Strip names from Value during LTO (other than GlobalValue)."),
76 #ifdef NDEBUG
77     cl::init(true),
78 #else
79     cl::init(false),
80 #endif
81     cl::Hidden);
82 
83 cl::opt<bool> LTOStripInvalidDebugInfo(
84     "lto-strip-invalid-debug-info",
85     cl::desc("Strip invalid debug info metadata during LTO instead of aborting."),
86 #ifdef NDEBUG
87     cl::init(true),
88 #else
89     cl::init(false),
90 #endif
91     cl::Hidden);
92 }
93 
LTOCodeGenerator(LLVMContext & Context)94 LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
95     : Context(Context), MergedModule(new Module("ld-temp.o", Context)),
96       TheLinker(new Linker(*MergedModule)) {
97   Context.setDiscardValueNames(LTODiscardValueNames);
98   Context.enableDebugTypeODRUniquing();
99   initializeLTOPasses();
100 }
101 
~LTOCodeGenerator()102 LTOCodeGenerator::~LTOCodeGenerator() {}
103 
104 // Initialize LTO passes. Please keep this function in sync with
105 // PassManagerBuilder::populateLTOPassManager(), and make sure all LTO
106 // passes are initialized.
initializeLTOPasses()107 void LTOCodeGenerator::initializeLTOPasses() {
108   PassRegistry &R = *PassRegistry::getPassRegistry();
109 
110   initializeInternalizeLegacyPassPass(R);
111   initializeIPSCCPLegacyPassPass(R);
112   initializeGlobalOptLegacyPassPass(R);
113   initializeConstantMergeLegacyPassPass(R);
114   initializeDAHPass(R);
115   initializeInstructionCombiningPassPass(R);
116   initializeSimpleInlinerPass(R);
117   initializePruneEHPass(R);
118   initializeGlobalDCELegacyPassPass(R);
119   initializeArgPromotionPass(R);
120   initializeJumpThreadingPass(R);
121   initializeSROALegacyPassPass(R);
122   initializePostOrderFunctionAttrsLegacyPassPass(R);
123   initializeReversePostOrderFunctionAttrsLegacyPassPass(R);
124   initializeGlobalsAAWrapperPassPass(R);
125   initializeLegacyLICMPassPass(R);
126   initializeMergedLoadStoreMotionLegacyPassPass(R);
127   initializeGVNLegacyPassPass(R);
128   initializeMemCpyOptLegacyPassPass(R);
129   initializeDCELegacyPassPass(R);
130   initializeCFGSimplifyPassPass(R);
131 }
132 
addModule(LTOModule * Mod)133 bool LTOCodeGenerator::addModule(LTOModule *Mod) {
134   assert(&Mod->getModule().getContext() == &Context &&
135          "Expected module in same context");
136 
137   bool ret = TheLinker->linkInModule(Mod->takeModule());
138 
139   const std::vector<const char *> &undefs = Mod->getAsmUndefinedRefs();
140   for (int i = 0, e = undefs.size(); i != e; ++i)
141     AsmUndefinedRefs[undefs[i]] = 1;
142 
143   // We've just changed the input, so let's make sure we verify it.
144   HasVerifiedInput = false;
145 
146   return !ret;
147 }
148 
setModule(std::unique_ptr<LTOModule> Mod)149 void LTOCodeGenerator::setModule(std::unique_ptr<LTOModule> Mod) {
150   assert(&Mod->getModule().getContext() == &Context &&
151          "Expected module in same context");
152 
153   AsmUndefinedRefs.clear();
154 
155   MergedModule = Mod->takeModule();
156   TheLinker = make_unique<Linker>(*MergedModule);
157 
158   const std::vector<const char*> &Undefs = Mod->getAsmUndefinedRefs();
159   for (int I = 0, E = Undefs.size(); I != E; ++I)
160     AsmUndefinedRefs[Undefs[I]] = 1;
161 
162   // We've just changed the input, so let's make sure we verify it.
163   HasVerifiedInput = false;
164 }
165 
setTargetOptions(const TargetOptions & Options)166 void LTOCodeGenerator::setTargetOptions(const TargetOptions &Options) {
167   this->Options = Options;
168 }
169 
setDebugInfo(lto_debug_model Debug)170 void LTOCodeGenerator::setDebugInfo(lto_debug_model Debug) {
171   switch (Debug) {
172   case LTO_DEBUG_MODEL_NONE:
173     EmitDwarfDebugInfo = false;
174     return;
175 
176   case LTO_DEBUG_MODEL_DWARF:
177     EmitDwarfDebugInfo = true;
178     return;
179   }
180   llvm_unreachable("Unknown debug format!");
181 }
182 
setOptLevel(unsigned Level)183 void LTOCodeGenerator::setOptLevel(unsigned Level) {
184   OptLevel = Level;
185   switch (OptLevel) {
186   case 0:
187     CGOptLevel = CodeGenOpt::None;
188     break;
189   case 1:
190     CGOptLevel = CodeGenOpt::Less;
191     break;
192   case 2:
193     CGOptLevel = CodeGenOpt::Default;
194     break;
195   case 3:
196     CGOptLevel = CodeGenOpt::Aggressive;
197     break;
198   }
199 }
200 
writeMergedModules(const char * Path)201 bool LTOCodeGenerator::writeMergedModules(const char *Path) {
202   if (!determineTarget())
203     return false;
204 
205   // We always run the verifier once on the merged module.
206   verifyMergedModuleOnce();
207 
208   // mark which symbols can not be internalized
209   applyScopeRestrictions();
210 
211   // create output file
212   std::error_code EC;
213   tool_output_file Out(Path, EC, sys::fs::F_None);
214   if (EC) {
215     std::string ErrMsg = "could not open bitcode file for writing: ";
216     ErrMsg += Path;
217     emitError(ErrMsg);
218     return false;
219   }
220 
221   // write bitcode to it
222   WriteBitcodeToFile(MergedModule.get(), Out.os(), ShouldEmbedUselists);
223   Out.os().close();
224 
225   if (Out.os().has_error()) {
226     std::string ErrMsg = "could not write bitcode file: ";
227     ErrMsg += Path;
228     emitError(ErrMsg);
229     Out.os().clear_error();
230     return false;
231   }
232 
233   Out.keep();
234   return true;
235 }
236 
compileOptimizedToFile(const char ** Name)237 bool LTOCodeGenerator::compileOptimizedToFile(const char **Name) {
238   // make unique temp output file to put generated code
239   SmallString<128> Filename;
240   int FD;
241 
242   const char *Extension =
243       (FileType == TargetMachine::CGFT_AssemblyFile ? "s" : "o");
244 
245   std::error_code EC =
246       sys::fs::createTemporaryFile("lto-llvm", Extension, FD, Filename);
247   if (EC) {
248     emitError(EC.message());
249     return false;
250   }
251 
252   // generate object file
253   tool_output_file objFile(Filename.c_str(), FD);
254 
255   bool genResult = compileOptimized(&objFile.os());
256   objFile.os().close();
257   if (objFile.os().has_error()) {
258     objFile.os().clear_error();
259     sys::fs::remove(Twine(Filename));
260     return false;
261   }
262 
263   objFile.keep();
264   if (!genResult) {
265     sys::fs::remove(Twine(Filename));
266     return false;
267   }
268 
269   NativeObjectPath = Filename.c_str();
270   *Name = NativeObjectPath.c_str();
271   return true;
272 }
273 
274 std::unique_ptr<MemoryBuffer>
compileOptimized()275 LTOCodeGenerator::compileOptimized() {
276   const char *name;
277   if (!compileOptimizedToFile(&name))
278     return nullptr;
279 
280   // read .o file into memory buffer
281   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
282       MemoryBuffer::getFile(name, -1, false);
283   if (std::error_code EC = BufferOrErr.getError()) {
284     emitError(EC.message());
285     sys::fs::remove(NativeObjectPath);
286     return nullptr;
287   }
288 
289   // remove temp files
290   sys::fs::remove(NativeObjectPath);
291 
292   return std::move(*BufferOrErr);
293 }
294 
compile_to_file(const char ** Name,bool DisableVerify,bool DisableInline,bool DisableGVNLoadPRE,bool DisableVectorization)295 bool LTOCodeGenerator::compile_to_file(const char **Name, bool DisableVerify,
296                                        bool DisableInline,
297                                        bool DisableGVNLoadPRE,
298                                        bool DisableVectorization) {
299   if (!optimize(DisableVerify, DisableInline, DisableGVNLoadPRE,
300                 DisableVectorization))
301     return false;
302 
303   return compileOptimizedToFile(Name);
304 }
305 
306 std::unique_ptr<MemoryBuffer>
compile(bool DisableVerify,bool DisableInline,bool DisableGVNLoadPRE,bool DisableVectorization)307 LTOCodeGenerator::compile(bool DisableVerify, bool DisableInline,
308                           bool DisableGVNLoadPRE, bool DisableVectorization) {
309   if (!optimize(DisableVerify, DisableInline, DisableGVNLoadPRE,
310                 DisableVectorization))
311     return nullptr;
312 
313   return compileOptimized();
314 }
315 
determineTarget()316 bool LTOCodeGenerator::determineTarget() {
317   if (TargetMach)
318     return true;
319 
320   TripleStr = MergedModule->getTargetTriple();
321   if (TripleStr.empty()) {
322     TripleStr = sys::getDefaultTargetTriple();
323     MergedModule->setTargetTriple(TripleStr);
324   }
325   llvm::Triple Triple(TripleStr);
326 
327   // create target machine from info for merged modules
328   std::string ErrMsg;
329   MArch = TargetRegistry::lookupTarget(TripleStr, ErrMsg);
330   if (!MArch) {
331     emitError(ErrMsg);
332     return false;
333   }
334 
335   // Construct LTOModule, hand over ownership of module and target. Use MAttr as
336   // the default set of features.
337   SubtargetFeatures Features(MAttr);
338   Features.getDefaultSubtargetFeatures(Triple);
339   FeatureStr = Features.getString();
340   // Set a default CPU for Darwin triples.
341   if (MCpu.empty() && Triple.isOSDarwin()) {
342     if (Triple.getArch() == llvm::Triple::x86_64)
343       MCpu = "core2";
344     else if (Triple.getArch() == llvm::Triple::x86)
345       MCpu = "yonah";
346     else if (Triple.getArch() == llvm::Triple::aarch64)
347       MCpu = "cyclone";
348   }
349 
350   TargetMach = createTargetMachine();
351   return true;
352 }
353 
createTargetMachine()354 std::unique_ptr<TargetMachine> LTOCodeGenerator::createTargetMachine() {
355   return std::unique_ptr<TargetMachine>(
356       MArch->createTargetMachine(TripleStr, MCpu, FeatureStr, Options,
357                                  RelocModel, CodeModel::Default, CGOptLevel));
358 }
359 
360 // If a linkonce global is present in the MustPreserveSymbols, we need to make
361 // sure we honor this. To force the compiler to not drop it, we add it to the
362 // "llvm.compiler.used" global.
preserveDiscardableGVs(Module & TheModule,llvm::function_ref<bool (const GlobalValue &)> mustPreserveGV)363 void LTOCodeGenerator::preserveDiscardableGVs(
364     Module &TheModule,
365     llvm::function_ref<bool(const GlobalValue &)> mustPreserveGV) {
366   SetVector<Constant *> UsedValuesSet;
367   if (GlobalVariable *LLVMUsed =
368           TheModule.getGlobalVariable("llvm.compiler.used")) {
369     ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
370     for (auto &V : Inits->operands())
371       UsedValuesSet.insert(cast<Constant>(&V));
372     LLVMUsed->eraseFromParent();
373   }
374   llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(TheModule.getContext());
375   auto mayPreserveGlobal = [&](GlobalValue &GV) {
376     if (!GV.isDiscardableIfUnused() || GV.isDeclaration())
377       return;
378     if (!mustPreserveGV(GV))
379       return;
380     if (GV.hasAvailableExternallyLinkage()) {
381       emitWarning(
382           (Twine("Linker asked to preserve available_externally global: '") +
383            GV.getName() + "'").str());
384       return;
385     }
386     if (GV.hasInternalLinkage()) {
387       emitWarning((Twine("Linker asked to preserve internal global: '") +
388                    GV.getName() + "'").str());
389       return;
390     }
391     UsedValuesSet.insert(ConstantExpr::getBitCast(&GV, i8PTy));
392   };
393   for (auto &GV : TheModule)
394     mayPreserveGlobal(GV);
395   for (auto &GV : TheModule.globals())
396     mayPreserveGlobal(GV);
397   for (auto &GV : TheModule.aliases())
398     mayPreserveGlobal(GV);
399 
400   if (UsedValuesSet.empty())
401     return;
402 
403   llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedValuesSet.size());
404   auto *LLVMUsed = new llvm::GlobalVariable(
405       TheModule, ATy, false, llvm::GlobalValue::AppendingLinkage,
406       llvm::ConstantArray::get(ATy, UsedValuesSet.getArrayRef()),
407       "llvm.compiler.used");
408   LLVMUsed->setSection("llvm.metadata");
409 }
410 
applyScopeRestrictions()411 void LTOCodeGenerator::applyScopeRestrictions() {
412   if (ScopeRestrictionsDone)
413     return;
414 
415   // Declare a callback for the internalize pass that will ask for every
416   // candidate GlobalValue if it can be internalized or not.
417   SmallString<64> MangledName;
418   auto mustPreserveGV = [&](const GlobalValue &GV) -> bool {
419     // Unnamed globals can't be mangled, but they can't be preserved either.
420     if (!GV.hasName())
421       return false;
422 
423     // Need to mangle the GV as the "MustPreserveSymbols" StringSet is filled
424     // with the linker supplied name, which on Darwin includes a leading
425     // underscore.
426     MangledName.clear();
427     MangledName.reserve(GV.getName().size() + 1);
428     Mangler::getNameWithPrefix(MangledName, GV.getName(),
429                                MergedModule->getDataLayout());
430     return MustPreserveSymbols.count(MangledName);
431   };
432 
433   // Preserve linkonce value on linker request
434   preserveDiscardableGVs(*MergedModule, mustPreserveGV);
435 
436   if (!ShouldInternalize)
437     return;
438 
439   if (ShouldRestoreGlobalsLinkage) {
440     // Record the linkage type of non-local symbols so they can be restored
441     // prior
442     // to module splitting.
443     auto RecordLinkage = [&](const GlobalValue &GV) {
444       if (!GV.hasAvailableExternallyLinkage() && !GV.hasLocalLinkage() &&
445           GV.hasName())
446         ExternalSymbols.insert(std::make_pair(GV.getName(), GV.getLinkage()));
447     };
448     for (auto &GV : *MergedModule)
449       RecordLinkage(GV);
450     for (auto &GV : MergedModule->globals())
451       RecordLinkage(GV);
452     for (auto &GV : MergedModule->aliases())
453       RecordLinkage(GV);
454   }
455 
456   // Update the llvm.compiler_used globals to force preserving libcalls and
457   // symbols referenced from asm
458   updateCompilerUsed(*MergedModule, *TargetMach, AsmUndefinedRefs);
459 
460   internalizeModule(*MergedModule, mustPreserveGV);
461 
462   ScopeRestrictionsDone = true;
463 }
464 
465 /// Restore original linkage for symbols that may have been internalized
restoreLinkageForExternals()466 void LTOCodeGenerator::restoreLinkageForExternals() {
467   if (!ShouldInternalize || !ShouldRestoreGlobalsLinkage)
468     return;
469 
470   assert(ScopeRestrictionsDone &&
471          "Cannot externalize without internalization!");
472 
473   if (ExternalSymbols.empty())
474     return;
475 
476   auto externalize = [this](GlobalValue &GV) {
477     if (!GV.hasLocalLinkage() || !GV.hasName())
478       return;
479 
480     auto I = ExternalSymbols.find(GV.getName());
481     if (I == ExternalSymbols.end())
482       return;
483 
484     GV.setLinkage(I->second);
485   };
486 
487   std::for_each(MergedModule->begin(), MergedModule->end(), externalize);
488   std::for_each(MergedModule->global_begin(), MergedModule->global_end(),
489                 externalize);
490   std::for_each(MergedModule->alias_begin(), MergedModule->alias_end(),
491                 externalize);
492 }
493 
verifyMergedModuleOnce()494 void LTOCodeGenerator::verifyMergedModuleOnce() {
495   // Only run on the first call.
496   if (HasVerifiedInput)
497     return;
498   HasVerifiedInput = true;
499 
500   if (LTOStripInvalidDebugInfo) {
501     bool BrokenDebugInfo = false;
502     if (verifyModule(*MergedModule, &dbgs(), &BrokenDebugInfo))
503       report_fatal_error("Broken module found, compilation aborted!");
504     if (BrokenDebugInfo) {
505       emitWarning("Invalid debug info found, debug info will be stripped");
506       StripDebugInfo(*MergedModule);
507     }
508   }
509   if (verifyModule(*MergedModule, &dbgs()))
510     report_fatal_error("Broken module found, compilation aborted!");
511 }
512 
513 /// Optimize merged modules using various IPO passes
optimize(bool DisableVerify,bool DisableInline,bool DisableGVNLoadPRE,bool DisableVectorization)514 bool LTOCodeGenerator::optimize(bool DisableVerify, bool DisableInline,
515                                 bool DisableGVNLoadPRE,
516                                 bool DisableVectorization) {
517   if (!this->determineTarget())
518     return false;
519 
520   // We always run the verifier once on the merged module, the `DisableVerify`
521   // parameter only applies to subsequent verify.
522   verifyMergedModuleOnce();
523 
524   // Mark which symbols can not be internalized
525   this->applyScopeRestrictions();
526 
527   // Instantiate the pass manager to organize the passes.
528   legacy::PassManager passes;
529 
530   // Add an appropriate DataLayout instance for this module...
531   MergedModule->setDataLayout(TargetMach->createDataLayout());
532 
533   passes.add(
534       createTargetTransformInfoWrapperPass(TargetMach->getTargetIRAnalysis()));
535 
536   Triple TargetTriple(TargetMach->getTargetTriple());
537   PassManagerBuilder PMB;
538   PMB.DisableGVNLoadPRE = DisableGVNLoadPRE;
539   PMB.LoopVectorize = !DisableVectorization;
540   PMB.SLPVectorize = !DisableVectorization;
541   if (!DisableInline)
542     PMB.Inliner = createFunctionInliningPass();
543   PMB.LibraryInfo = new TargetLibraryInfoImpl(TargetTriple);
544   PMB.OptLevel = OptLevel;
545   PMB.VerifyInput = !DisableVerify;
546   PMB.VerifyOutput = !DisableVerify;
547 
548   PMB.populateLTOPassManager(passes);
549 
550   // Run our queue of passes all at once now, efficiently.
551   passes.run(*MergedModule);
552 
553   return true;
554 }
555 
compileOptimized(ArrayRef<raw_pwrite_stream * > Out)556 bool LTOCodeGenerator::compileOptimized(ArrayRef<raw_pwrite_stream *> Out) {
557   if (!this->determineTarget())
558     return false;
559 
560   // We always run the verifier once on the merged module.  If it has already
561   // been called in optimize(), this call will return early.
562   verifyMergedModuleOnce();
563 
564   legacy::PassManager preCodeGenPasses;
565 
566   // If the bitcode files contain ARC code and were compiled with optimization,
567   // the ObjCARCContractPass must be run, so do it unconditionally here.
568   preCodeGenPasses.add(createObjCARCContractPass());
569   preCodeGenPasses.run(*MergedModule);
570 
571   // Re-externalize globals that may have been internalized to increase scope
572   // for splitting
573   restoreLinkageForExternals();
574 
575   // Do code generation. We need to preserve the module in case the client calls
576   // writeMergedModules() after compilation, but we only need to allow this at
577   // parallelism level 1. This is achieved by having splitCodeGen return the
578   // original module at parallelism level 1 which we then assign back to
579   // MergedModule.
580   MergedModule = splitCodeGen(std::move(MergedModule), Out, {},
581                               [&]() { return createTargetMachine(); }, FileType,
582                               ShouldRestoreGlobalsLinkage);
583 
584   // If statistics were requested, print them out after codegen.
585   if (llvm::AreStatisticsEnabled())
586     llvm::PrintStatistics();
587 
588   return true;
589 }
590 
591 /// setCodeGenDebugOptions - Set codegen debugging options to aid in debugging
592 /// LTO problems.
setCodeGenDebugOptions(const char * Options)593 void LTOCodeGenerator::setCodeGenDebugOptions(const char *Options) {
594   for (std::pair<StringRef, StringRef> o = getToken(Options); !o.first.empty();
595        o = getToken(o.second))
596     CodegenOptions.push_back(o.first);
597 }
598 
parseCodeGenDebugOptions()599 void LTOCodeGenerator::parseCodeGenDebugOptions() {
600   // if options were requested, set them
601   if (!CodegenOptions.empty()) {
602     // ParseCommandLineOptions() expects argv[0] to be program name.
603     std::vector<const char *> CodegenArgv(1, "libLLVMLTO");
604     for (std::string &Arg : CodegenOptions)
605       CodegenArgv.push_back(Arg.c_str());
606     cl::ParseCommandLineOptions(CodegenArgv.size(), CodegenArgv.data());
607   }
608 }
609 
DiagnosticHandler(const DiagnosticInfo & DI,void * Context)610 void LTOCodeGenerator::DiagnosticHandler(const DiagnosticInfo &DI,
611                                          void *Context) {
612   ((LTOCodeGenerator *)Context)->DiagnosticHandler2(DI);
613 }
614 
DiagnosticHandler2(const DiagnosticInfo & DI)615 void LTOCodeGenerator::DiagnosticHandler2(const DiagnosticInfo &DI) {
616   // Map the LLVM internal diagnostic severity to the LTO diagnostic severity.
617   lto_codegen_diagnostic_severity_t Severity;
618   switch (DI.getSeverity()) {
619   case DS_Error:
620     Severity = LTO_DS_ERROR;
621     break;
622   case DS_Warning:
623     Severity = LTO_DS_WARNING;
624     break;
625   case DS_Remark:
626     Severity = LTO_DS_REMARK;
627     break;
628   case DS_Note:
629     Severity = LTO_DS_NOTE;
630     break;
631   }
632   // Create the string that will be reported to the external diagnostic handler.
633   std::string MsgStorage;
634   raw_string_ostream Stream(MsgStorage);
635   DiagnosticPrinterRawOStream DP(Stream);
636   DI.print(DP);
637   Stream.flush();
638 
639   // If this method has been called it means someone has set up an external
640   // diagnostic handler. Assert on that.
641   assert(DiagHandler && "Invalid diagnostic handler");
642   (*DiagHandler)(Severity, MsgStorage.c_str(), DiagContext);
643 }
644 
645 void
setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,void * Ctxt)646 LTOCodeGenerator::setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,
647                                        void *Ctxt) {
648   this->DiagHandler = DiagHandler;
649   this->DiagContext = Ctxt;
650   if (!DiagHandler)
651     return Context.setDiagnosticHandler(nullptr, nullptr);
652   // Register the LTOCodeGenerator stub in the LLVMContext to forward the
653   // diagnostic to the external DiagHandler.
654   Context.setDiagnosticHandler(LTOCodeGenerator::DiagnosticHandler, this,
655                                /* RespectFilters */ true);
656 }
657 
658 namespace {
659 class LTODiagnosticInfo : public DiagnosticInfo {
660   const Twine &Msg;
661 public:
LTODiagnosticInfo(const Twine & DiagMsg,DiagnosticSeverity Severity=DS_Error)662   LTODiagnosticInfo(const Twine &DiagMsg, DiagnosticSeverity Severity=DS_Error)
663       : DiagnosticInfo(DK_Linker, Severity), Msg(DiagMsg) {}
print(DiagnosticPrinter & DP) const664   void print(DiagnosticPrinter &DP) const override { DP << Msg; }
665 };
666 }
667 
emitError(const std::string & ErrMsg)668 void LTOCodeGenerator::emitError(const std::string &ErrMsg) {
669   if (DiagHandler)
670     (*DiagHandler)(LTO_DS_ERROR, ErrMsg.c_str(), DiagContext);
671   else
672     Context.diagnose(LTODiagnosticInfo(ErrMsg));
673 }
674 
emitWarning(const std::string & ErrMsg)675 void LTOCodeGenerator::emitWarning(const std::string &ErrMsg) {
676   if (DiagHandler)
677     (*DiagHandler)(LTO_DS_WARNING, ErrMsg.c_str(), DiagContext);
678   else
679     Context.diagnose(LTODiagnosticInfo(ErrMsg, DS_Warning));
680 }
681